Vol.6 No. 4 



TORREYA 



April, 1906 



LIBRARY 



ABNORMALITIES IN THE FRUITING HABITS NEW YORK 



OF OPUNTIAS BOTANICAL 



(iARDEN. 



By David Griffiths 



There have appeared recently an article by Professor Toumey,* 

 which was reviewed by Dr. Harris, t and a note by Dr. Cannon, J 

 depicting certain abnormalities found in the fruiting habits of the 

 genus Opiintia, Professor Tourney's brochure using these abnor- 

 malities to prove the caulome origin of the fruit and Dr. Can- 

 non's simply to record an observation upon a single specimen. 

 Besides the above there is much literature upon this subject, ref- 

 erence to which need not be made here, inasmuch as Mr. Harris 

 quotes a considerable part of it in the above review. There is, 

 however, more to be said upon this subject and it is my object 

 to record some observations and investigations which have been 

 made during the past five years, with little attempt, however, at 

 generalization except to show an apparent relation between ster- 

 ility of fruit and its assumption of the character of the stem. 



To me the strongest evidence of the caulome nature of the 

 fruit is to be found in its leaves subtending pulvini which there is 

 strong evidence for considering modified branches. In a few 

 species there is not only a development of spines and spicules 

 from the pulvini for a number of years after the maturity of the 

 joint but also a distinct development of the tissue of the pulvinus 

 itself into a columnar structure (modified stem) sometimes an 

 inch long. These structures develop gradually for ten years or 



*Bull. Torrey Club 32 : 235. 1905. 

 t Bull. Torrey Club 32 : 531. 1905. 

 :0 JT0RREYA5: 216. 1905. 



Zi'i 



— [No. 3, Vol. 6, of ToRREYA, comprising pages 41-56, was issued March 16, 



■■- 1906.1 



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